Shanghai Key Laboratory of Molecular Imaging, Jiading District Central Hospital Affiliated Shanghai University of Medicine and Health Sciences, Shanghai, China; Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang, China.
School of Pharmacy, Shanghai University of Medicine and Health Sciences, Shanghai, China.
Cell Signal. 2024 Dec;124:111468. doi: 10.1016/j.cellsig.2024.111468. Epub 2024 Oct 10.
Lactylation, a newly identified post-translational modification, is uncertain in its implication in triple-negative breast cancer (TNBC). In this study, we analyzed 60 TNBC samples using immunohistochemical staining and revealed elevated levels of pan-lactylated proteins and specific histone H4K12 lactylation in tumor tissues, correlating with TNBC progression. Lactate exposure in TNBC cell lines significantly induced lysine lactylation at the H4K12 site, leading to alterations in gene profiles and reduced apoptosis. These effects were attenuated by DCA or sodium Oxamate, inhibitors of endogenous lactate production. Gene sequencing showed an increase in Schlafen 5 (SLFN5) expression in TNBC cells treated with Oxamate, contrasting with the effects of lactate exposure. Analysis of TNBC tissues showed a negative correlation between H4K12 lactylation and SLFN5 protein levels. Overexpression of SLFN5 countered the effects of lactate on apoptosis and tumor growth, highlighting its pivotal role in TNBC malignancy. CUT&Tag sequencing indicated that lactylated H4K12 potentially binds to the SLFN5 promoter region. Luciferase reporter assays further verified that lactate-induced suppression of SLFN5 promoter activity is mediated by wild-type H4K12, but not by its R or A mutants, verified by both in vitro and in vivo apoptosis detection in response to lactate and Oxamate stimulation. These results establish that H4K12 lactylation, induced by lactate in TNBC cells, specifically suppresses SLFN5 expression, contributing to TNBC malignancy. Our findings illuminate a critical histone lactylation-dependent carcinogenic pathway in TNBC.
乳酰化作用，一种新发现的翻译后修饰方式，其在三阴性乳腺癌（TNBC）中的意义尚不确定。在本研究中，我们使用免疫组织化学染色分析了 60 例 TNBC 样本，结果显示肿瘤组织中存在泛乳酰化蛋白和特定的组蛋白 H4K12 乳酰化水平升高，与 TNBC 进展相关。TNBC 细胞系中乳酸的暴露显著诱导了 H4K12 位点赖氨酸的乳酰化，导致基因谱的改变和细胞凋亡减少。这些效应被内源性乳酸产生的抑制剂 DCA 或 Sodium Oxamate 减弱。基因测序显示，Oxamate 处理的 TNBC 细胞中 Schlafen 5（SLFN5）的表达增加，与乳酸暴露的影响相反。对 TNBC 组织的分析显示，H4K12 乳酰化与 SLFN5 蛋白水平呈负相关。SLFN5 的过表达抵消了乳酸对细胞凋亡和肿瘤生长的影响，突出了其在 TNBC 恶性肿瘤中的关键作用。CUT&Tag 测序表明，乳酰化的 H4K12 可能与 SLFN5 启动子区域结合。荧光素酶报告基因检测进一步证实，乳酸诱导的 SLFN5 启动子活性抑制是由野生型 H4K12 介导的，而不是由其 R 或 A 突变体介导的，这在体外和体内的凋亡检测中都得到了验证，对乳酸和 Oxamate 的刺激都有反应。这些结果表明，TNBC 细胞中乳酸诱导的 H4K12 乳酰化特异性抑制 SLFN5 的表达，促进了 TNBC 的恶性肿瘤。我们的研究结果揭示了 TNBC 中一种关键的组蛋白乳酰化依赖性致癌途径。
